The answer is D) 12
If you need proof, just comment.
Let p be the prize of a pen and m the prize of a mechanical pencils. If you buy six pens and one mechanical pencil, you spend 6p+m. We know that this equals 9, because you get 1$ change from a 10$ bill.
Similarly, if you buy four pens and two mechanical pencils, you spend 4p+2m, which is 8$, because now you get a $2 change. Put these equation together in a system:
Now, if you multiply the first equation by 2, the system becomes
Subtract the second equation from the first:
Plug this value into the first equation to get
You first need to cross multiply to get 8x+8=6x^2-6. Then make the function into 6x^2-8x-14=0 which can be simplified into 3x^2-4x-7=0 by dividing the equation by 2. Then you must split the middle(-4x) to get 3x^2+3x-7x-7=0. This simplifies to 3x(x+1)-7(x+1)=0 and then to (3x-7)(x+1)=0. From here you just solve for each root which you will find are x= -1 and 7/3
Answer:
B
Step-by-step explanation:
2x+x=180
3x=180
x=60
2x=120
so B
hope that helps if it does please mark mine as brainliest.
10= -4 + x x=14 because you do the opposite of the sign you see in this case its a plus sign so you subtract -4 from ten and since the 4 is a negative and your subtracting you would add 4 I know this probably didn't help it sounds really confusing but I have hope that it did :)
